DefinePK

Abstract

Ultra-wideband (UWB) communication systems have the promise of very high bandwidth, reduced fading from multipath and low power requirements. Band width can be extended to higher frequencies by adding a Octagonal or Hexagonal strip horizontally from the printed radiator and asymmetrically attaching a conducting strip to the radiator. This paper reports about the design of the antennas to enhance the bandwidth by increasing the size of the strip monopole by different geometries. The geometry of the wide Octagonal strip monopole is a Octagon of side 'a=9mm' where as for the wide Hexagon monopole is a Hexagon of side ‘a=10mm’.The strip length is 23mm and small gap 'd=3mm' between ground planes and strip for both the antenna geometries to achieve matching. The two printed monopole antennas are designed are etched onto a FR-4 epoxy substrate with an overall size of 45mm × 60mm ×1.6 mm. The proposed antennas are simulated using Ansoft HFSS and the practical results are obtained by testing the patches on Vector Network Analyzer. The Hexagonal strip monopole is resonating at 5.5 GHz and UWB impedance bandwidth (S11 < –10 dB) ranges from 1.54 to 9.41GHz, while the Octagonal strip monopole is resonating at 5.5GHz and UWB impedance bandwidth (S11 < –10 dB) ranges from 1.3 to 5.65 GHz. The VSWR values for Hexagonal is 1.52:1 at 2.09GHz & for Octagonal it is 1.53:1 at 1.78GHz.The Bandwidth for Hexagonal is 7.87GHz, while for Octagonal is 4.35GHz.